• Cenozoic biogenic silica sedimentation in the Antarctic ...

    Cenozoic biogenic silica sedimentation in the Antarctic Ocean, ... The efficiency of surface productivity has progressed to such an extent that much of the global silica supply has been transferred to the Antarctic at the expense of other productive oceanic regions such as the Central Equatorial Pacific. In the Neogene, the preservation or ...

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  • A Shift in the Biogenic Silica of Sediment in the Larsen B ...

    Biogenic silica is major constituent of Antarctic marine sediment, and its presence in the sediment column is associated with diatom production in the euphotic zone. The abundance of diatom valves and the number of sponge spicules in the biogenic silica was analyzed to determine how the origin of the biogenic silica in the upper layers of the ...

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  • (PDF) Biogenic Silica - ResearchGate | Share and discover ...

    Amorphous silica, e.g. biogenic silica (BSi), contained in diatoms and in sponge spicules was estimated by time course extraction from surficial sediment samples of 82 Florida lakes.

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  • USGS Open-File Report 02-371, Geochemical Sediment ...

    Biogenic Silica : The WHFC has the capability to digest sediment samples to be further analyzed by Inductively Coupled Plasma - Emission Spectrometry (ICP-ES) for biogenic silica. Biogenic silica fluxes indicate ecosystem productivity over time.

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  • Biogenic Silica - an overview | ScienceDirect Topics

    Biogenic silica, or opal, is the second biogenic material that dominates many marine sediments. Like CaCO 3, ... There is increasing evidence in support of the breakdown and reprecipitation of siliceous minerals in a variety of sedimentary environments, including …

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  • Biogenic silica recycling in surficial sediments across ...

    The processes controlling preservation and recycling of particulate biogenic silica in superficial sediments must be understood before one uses biogenic silica as a proxy in paleooceanographic studies, and in order to compute oceanic mass balances for silica.

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  • Accounting for the Missing Silica in the Marine Sediment ...

    Accounting for the Missing Silica in the Marine Sediment Cycle . Cosmogenic silicon-based estimates of the amount of biogenic silica stored in clays …

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  • Biogenic silica sedimentation in the central equatorial ...

    The percent of biogenic silica in the sediments varies synchronously with the accumulation rates, but is low to the east due to dilution by non-biogenic sediment from terrigenous and volcanic sources.

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  • Biogenic Silica Burial Efficiency in Cascadia Basin Sediments

    So while the biogenic silica burial rate initially calculated provides an upper limit for burial, a more accurate rate can be calculated using sedimentation rates as determined by Hedges et al .

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  • Human Influence on Diatom Productivity and Sedimentation ...

    A paper entitled "Anthropogenically Induced Changes in Sediment and Biogenic Silica Fluxes in Chesapeake Bay," written by Steve Colman and John Bratton, has been published in the journal Geology (January 2003).

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  • Biogenic Silica | SpringerLink

    The measurement of the biogenic silica (BSi) content of sediments is a chemical estimate of the siliceous microfossil abundance. Briefly, sediments are leached with a weak base, usually Na 2 CO 3, for a period of time (2–5 hours), and aliquots withdrawn over time. The aliquots are then measured ...

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  • Biogenic silica in tidal freshwater marsh sediments and ...

    sediment the largest BSi reservoir in the marsh. We conclude that P. australis wetlands could be an essential, but unrecognised, sink for BSi in the biogeochemical cycling of Si. KEY WORDS: Biogenic silica · Freshwater marsh · Estuary · Phragmites australis· Eutrophication · Impatiens glandulifera · Sediment

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  • 7.04 The Diagenesis of Biogenic Silica: Chemical ...

    B the concentration of “reactive” biogenic silica per volume of sediment (mol cm23) C the pore-water silicate concentration (mol cm23) C s the pore-water asymptotic silicate value observed at depth in the sediment column (mol cm23) D B sediment bioturbation coefficient (cm2 yr21) D

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  • Marine Sediments - University of Florida

    Marine Sediments. Variety of possible sources: From continents (rivers, wind, ice) ... = biogenic sediment. Biogenic material is generally overwhelmed by terrigenous material; ... SiO 2 = silica; Diatoms Radiolarians Coccolithophores Foraminifera. Biogenic Sediment.

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  • Biogenic silica - Wikipedia

    Rates of biogenic silica dissolution in surface sediments are quite variable, with rates at least an order of magnitude lower than in the water column and decreasing to virtually zero at sediment …

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  • Dissolution kinetics of biogenic silica from ... - DeepDyve

    Dissolution kinetics of biogenic silica from the water column to the sediments We investigated the dissolution kinetics of uncleaned and chemically cleaned BSi collected in ocean surface water, sediment traps, and sediments from the Norwegian Sea, the Southern Ocean, and the Arabian Sea.

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  • Sedimentary Records of Environmental Change Lab – School ...

    Biogenic-silica content (wet-alkaline extraction) quantifies the weight percent of algal remains in sediment. It can be used to infer past changes in aquatic productivity and, in some cases, serves as a useful climate proxy. Sediment can be analyzed rapidly at high resolution.

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  • Organic carbon and biogenic silica in marine sediments in ...

    Biogenic silica was measured following a sequential alkaline oxi-dation (NaCO 3) based on the method of Mortlock and Froelich (1989) modified by DeMaster (1991). Organic carbon and biogenic silica inventories were calculated multiplying each variable content by the thick-ness of the correspondent sediment slice and its dry bulk

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  • Production and dissolution of biogenic silica in the ocean ...

    Production and dissolution of biogenic silica in the ocean: Revised global estimates, comparison with regional data and relationship to biogenic sedimentation. Authors. David M. Nelson, Paul Tréguer, Mark A. Brzezinski, ... The estimated production of biogenic silica in surface waters of the mid-ocean gyres is approximately equal to that for ...

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  • Biogenic Sediments | Actforlibraries.org

    Biogenic sediments are the skeletal remains of either plant or animal marine species. The hard skeletal structures of marine organisms are important constituents of the deep ocean sediment and many layers of the deep ocean floor are almost entirely composed of calcareous and siliceous skeletal remains.

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  • LacCore SOP series Biogenic Silica Analysis Purpose ...

    To determine the percent biogenic silica in sediments using sodium hydroxide dissolution of silica and molybdate blue spectrophotometry. Principle A freeze dried sediment sample is placed in hot sodium hydroxide to dissolve the silica in the sample. The dissolved silica comes from biogenic sources, i.e. diatoms, and non-biogenic sources, i.e ...

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  • Biogenic Silica in the Devonian Shale Succession of the ...

    Biogenic Silica in the Devonian Shale Succession of the Appalachian Basin, USA* Randy Blood1, Gary Lash2, and Lindell Bridges1 Search and Discovery Article #50864 (2013)** Posted September 23, 2013 *Adapted from oral presentation given at AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013

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  • (PDF) Biogenic Silica - researchgate.net

    trends from diatoms and biogenic silica in the sediment and the pelagic zone of Lake Constance. ... biogenic opal has limited durability in sodic and calcareous soils. Therefore, the effect of ...

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  • Biogenic Sediments - Department of Geology

    The depth of the CCD and the pattern of carbonate sedimentation in any part of the world's ocean reflects the influences of surface production of organic matter, surface production of carbonates, ... resulting in carbonate oozes that are poor in biogenic silica and vice versa.

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  • Limnological investigation of biogenic silica ...

    soluble silica extracted with carbonate leaching by the sediment dry weight. The biogenic silica concentration and the mass sedimentation rate were then used to calculate the annual flux or sedimentation rate of biogenic silica as g $102 9 m _2 -. yr _ for each sampling interval. Results

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  • Potential deposition of biogenic silica source sediment in ...

    ABSTRACT. Biogenic silica sediment constitutes one of the critical sources of particle income in the oceans. In this paper, satellite remote sensing of primary production, sinking flux, and molar ratio of Si/C were utilized to elucidate potential biogenic silica sediment in the …

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  • APPENDIX E BIOGENIC SILICA ASSESSMENT OF SEDIMENT …

    BIOGENIC SILICA ASSESSMENT OF SEDIMENT SAMPLES FROM THE SOIL PROFILE AND SELECT CULTURAL FEATURES AT 41TV2161 J. Byron Sudbury1 Ph.D. E.1 SUMMARY The Big Hole Site (41TV2161) is located on a floodplain in Travis County, Texas, on a relict paleochannel near Onion Creek above its juncture

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  • Standard Operating Procedures for Determining Total ...

    silica pool are corrected for by using a timed extraction procedure and the differential rates of extraction for biogenic bersus mineral forms (DeMaster 1981). Prior to Analysis: 3.1.1 Weigh 25-35 mg for clay/silty sediment or 50-70 mg for sandy sediment of freeze-dried, homogenized, sediment on the Mettler AT250 balance. Calibrate balance at ...

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  • Cycling of organic carbon and biogenic silica in the ...

    We deployed sediment traps from January, 1990 to early March, 1992 to measure the mid‐water (250 m) and near‐bottom gravitational fluxes of particulate organic carbon, nitrogen and biogenic silica year‐round at three sites, and obtained sediment cores at 15 sites to assess the accumulation rates of organic carbon and biogenic silica in ...

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  • APPENDIX J BIOGENIC SILICA ASSESSMENT OF SEDIMENT …

    BIOGENIC SILICA ASSESSMENT OF SEDIMENT SAMPLES FROM 41MS69 J. Byron Sudbury, Ph.D. J.1 SUMMARY Five sediment samples, two old geomorphic samples and three from cultural Features 1 and 2, were processed for biogenic silica recovery and analysis. Overall biogenic silica preservation was very poor due to the basic pH environment of the

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